Method of laminating



Dec. 13, 1955 F. A. GRANT METHOD OF LAMINATING Filed July 22, 1952INVENTOR Fkm/x A. 6729; BY

ATTORNEY United States Patent METHOD or LAMINATING Frank A. Grant,Richmond, Va., assignor, by mesne assignments, to Continental CanCompany, Inc., New York, N. Y., a corporation of New York ApplicationJuly 22, 1952, Serial No. 300,236

3 Claims. (Cl. 154-129) It is an object of this invention to provide amethod and apparatus for laminating at least three webs by a singlecontinuous operation, the method and apparatus being especially usefulwhere one of the webs is of highly impervious barrier material.

It is a further object of this invention to provide a method andapparatus as aforesaid in which the laminating agent is applied to onlyone intermediate Web.

It is a further object of this invention to provide a method andapparatus as aforesaid in which the job of threading and rethreading isextremely simple.

It is a further object of this invention to provide a method andapparatus as aforesaid in which there are available a variety ofcontrols permitting the application of the method and apparatus to websof greatly varying strength, caliper and porosity.

The above and other objects will be made clear from the followingdetailed description taken in connection with the annexed drawing.

A laminated sheet which has developed considerable utility in the lastfew years comprises a ply of metallic foil laminated to a ply of tissueby means of micro-crystalline wax. A second ply of tissue is laminatedto the first tissue ply by means of micro-crystalline wax which doesnot, however, completely penetrate the second ply. The laminated webaccordingly presents wax-free surfaces on both sides but when the web isformed into bags and the bags are subjected to heat and pressure the waxbleeds through the outermost tissue lamination and forms an excellentheat seal.

The present invention takes advantage of the penetrating power ofmicro-crystalline wax on tissue to efiect a one-step lamination by theapplication of wax to one side only of the intermediate sheet.

Referring now to the drawing, there is shown a supply roll of tissuepaper from which a web 12 is fed over a vertically adjustable guide roll14, thence over a guide roll 16 to a guide roll 18. The web 12 forms aloop between the rolls 16 and 18 and a dancing roll 20 is supported inthe loop and assures uniform tension on the web. A coating roll 22revolves partially immersed in a vat 24 of molten micro-crystalline wax.

A guide roll 26 presses the web 12 into contact with the roll 22 and isvertically adjustable to determine the extent of contact between the web12 and the coating roll 22. From the coating roll 22 the web is drawnover a doctor wire 28 which removes excess wax. A smoothing bar 30receives the web from the doctor wire 28 and the extent of pressurebetween the web 12 and the wire 28 and the smoothing bar 30 isdetermined by a spreader bar 32.

The supply roll 34 delivers a web of foil 36 to a straightening roll 38,thence to a guide roll 40 and thence to a laterally adjustable guideroll 42. The lateral adjustment of the roll 42 determines the extent ofwrap of the foil web 36 around a controlled temperature roll 44 which ismade vertically adjustable for the purpose of 2,726,979 Patented Dec-.13, 1 5

reg lat ng the exten of wrapof the. up r mposed .foil web 36 and coatedtissue web 12.

The supply roll 46 delivers a second tissue web 48 to a Pair of t n ining 1 11s 0 an t n to a om ine r0 1 52 which also receives from thecontrolled temperature roll 44 the superimposed coated tissue Web 12 andfoil web 36.

Th emper ture of th rol 44 is such that t Wax applied to the web 12 willpenetrate through thatweb and eifect a bond between it and the foil web36. The temperature of the combining roll 52 is controlled so that thewax on the web 12 will penetrate only partly into the second tissue web48 and effect a bond but will not provide a waxy exterior surface to thefinal lamination.

A rubber pressure roll 54 bears on the combining roll 52 and assures aproper meeting and lamination of the three webs.

From the knit of the rubber roll 54 the combined web passes over a firstchilled or refrigerated roll 56 then to a second chilled or refrigeratedroll 58 from which the laminated webs pass to a first tempering roll 60,a second tempering roll 62, a guide roll 64 and a rewind roll 66.

A typical laminating operation involves the web 36, being made of .00035foil with the webs 12 and 48 formed of smooth tissue weighing 10 /2 lbs.per ream with the coating roll 22 applying about 15 lbs. per ream ofmicro-crystalline wax containing a small amount of colloidal matter. Insuch an operation the wax is maintained in the vat at about 195 F. Inpractice the vat temperatures may range between and 210 depending on thejob to be done. The surface speed of the coating roll 22 does notnecessarily match the lineal speed of the web 12. The roll 22 is rotatedat a speed sufficient to ensure that it will pick up an adequate supplyof wax somewhat in excess of the amount intended to remain on the web12, the excess being removed by the doctor wire 28.

The tempering rolls 60 and 62 are necessary where the lineal speed ofthe whole operation is high and where it is desired not fully to chillthe wax on the relatively small diameter rolls 56 and 58. In such casethe final chill is applied by the tempering rolls of relatively largediameter, thus tending to avoid the formation of pin-hole cracks in thewax.

It will be clear from the foregoing that the apparatus may be made quitecompact, that the threading and rethreading job is much simplified andthat the controls, though simple, are sufficiently varied to enable theapparatus to meet any laminating problem apt to be encountered.

While certain specific embodiments of the invention have beenillustrated and described, it is not intended to limit the invention tothe precise details disclosed but only as set forth in the snbjoinedclaims which are to be broadly construed.

I claim:

1. A method of laminating comprising: coating one side only of a singlepervious web with molten microcrystalline wax; causing said wax topenetrate through said pervious web while superimposing an imperviousweb on the side of said pervious web opposite that to which the coatingwas applied; superimposing a pervious web on the original coated side ofthe first named pervious web, causing said wax to penetrate said secondpervious web while limiting the penetration to less than the thicknessof said second pervious web.

2. A method of laminating comprising: continuously and simultaneouslyadvancing a web of metallic foil, a first tissue web and a second tissueweb; applying a coating of molten, micro-crystalline wax to one sideonly of said first tissue web; superimposing the uncoated side of saidfirst tissue web on the web of metallic foil at a temperaturesutficientto cause penetration of the wax through the tissue to cause adhesionbetween the foil and the tissue; thereafter superimposing said secondtissue web on the coated side of the first tissue web at a temperaturesuflicient to cause partial penetration by the wax of the second tissueweb and adhesion between the two tissue webs.

3. A method as set forth in claim 2 in which the weight per ream of waxapplied exceeds the weight per ream of the first tissue web.

- References Cited in the file of this patent UNITED STATES PATENTSne.22,130 Grant July 7, 1942 Y 1,217,819 Peterson Feb. 27, 19172,031,036 Dreymann Feb; 18,1936 2,158,754 Hodgdon May 16, 1939 2,212,122Miller Aug. 20, 1940 2,434,795 Glasing et a1. Jan. 20, 1948 2,474,619Farrell et a1. June 28, 1949 10 John C. Dean, Paper Trade Journal, vol.120, No. 7, Feb.

15, 1945, pages 28-32 (Fig. 3 sh0ws"apparatus)

2. A METHOD OF LAMINATING COMPRISING: CONTINUOUSLY AND SIMULTANEOUSLYADVANCING A WEB OF METALLIC FOIL, A FIRST TISSUE WEB AND A SECOND TISSUEWEB; APPLYING A COATING OF MOLTEN, MICRO-CRYSTALLINE WAX TO ONE SIDEONLY OF SAID FIRST TISSUE WEB; SUPERIMPOSING THE UNCOATED SIDE OF SAIDFIRST TISSUE WEB ON THE WEB OF METALLIC FOIL AT A TEMPERATURE SUFFICIENTTO CAUSE PENETRATION OF THE WAX THROUGH THE TISSUE TO CAUSE ADHESIONBETWEEN THE FOIL AND THE TISSUE; THEREAFTER SUPERIMPOSING SAID SECONDTISSUE WEB ON THE COATED SIDE OF THE FIRST TISSUE WEB AT A TEMPERATURESUFFICIENT TO CAUSE PARTIAL PENETRATION BY THE WAX OF THE SECOND TISSUEWEB AND ADHESION BETWEEN THE TWO TISSUE WEBS.